"The process of becoming this crazy and brainwashed legit deserves a thorough analysis."
Yes, this begins with focusing all of your attention on the worst attributes on the other side. She probably spent the last years thinking all conservatives were Nazis. Now the way to not fall into this trap yourself is to not focus your time on the worst the other side has to offer.
The different between the right and left at this point is that this person would never make it anywhere within the power structure of the Democratic party, whereas if she supported Trump he would make sure to make her Secretary of the Interior or some shit.